压痕-急冷法测定增韧氧化铝基陶瓷复合材料的抗热震性能

INDENTATION-QUENCH METHOD TO DETERMINE THE THERMAL SHOCK RESISTANCE FOR TOUGHING Al_2O_3 CERAMIC MATRIX COMPOSITES

采用压痕 急冷法测试了Al2 O3 SiCw ,Al2 O3 ZrO2 和Al2 O3 TiCp三种陶瓷基复合材料的抗热震性能 ,并与急冷强度法测试结果进行了对比分析。实验结果表明 ,两种方法之间存在一致性。三种陶瓷基复合材料与基体Al2 O3 相比抗热震性均有较大幅度的提高 ,其中Al2 O3 SiCw复合材料显示出最为优越的抗裂纹扩展能力与抗循环热震性能。材料的增韧效果是产生这一现象的主要原因。压痕 急冷法与急冷强度法相比免去了热震后的强度测试 ,具有使用试样数目少 ,数据具有统计效应 。

The thermal shock resistance of the Al_2O_3-SiCw,Al_2O_3-ZrO_2,and Al_2O_3-TiCp ceramic matrix composites were measured by the indentation-quench test. The results of the test were compared with the results of quenching test. The results show that the two methods are consistent and the three kinds of composites exhibited better thermal shock resistance than their matrix. The Al_2O_3-SiCw composite, however, displayed the best resistant to crack extension and higher cyclic thermal shock resistance. From SEM observation and theoretical analysis, it was inferred that this phenomena could be attributed mainly to the microstructure and the toughing mechanism of the materials. The indentation-quench test avoids subsequent mechanical testing, by using a small number of specimens, and the reliable statistical data can be obtained, and also the propagation of the crack can be observed directly.